"In early 2009, Nintendo announced the Classic Controller Pro which functions the same as the original Classic Controller with the exception of the shoulder buttons, which are now digital trigger-shaped buttons arranged vertically rather than horizontally. Instead of a SNES controller, this one is shaped more like a GameCube controller. It also features a shiny coating on the frontside, which makes fingerprints more visible. Physical changes include the ZL and ZR buttons, which are now full shoulder buttons, the addition of grips underneath the controller for additional stability, and analog sticks which are spaced farther apart than the original. The cord is positioned on top of the controller rather than the bottom, and the spring-loaded attachment slot underneath the original model was removed. The Pro version was first released to Japan in August 2009 in white and black versions. It was subsequently released to Europe and North America in November 2009 and April 2010, respectively (though only in black in Europe). The black version is available bundled with Monster Hunter Tri, Pro Evolution Soccer 2010, and SD Gundam Gashapon Wars. In addition to the standard colors, a black version with gold-colored artwork on the face was available bundled with Samurai Warriors 3 in Japan, and a completely gold-colored version is available bundled in the GoldenEye 007 Classic Edition. A red version was packed with limited copies of Xenoblade Chronicles in Europe."
Source: Wikipedia, "Classic Controller Pro", available under the CC-BY-SA License.